A method for treating cold rolling rolls suitable for high surface quality titanium alloy sheet

Abstract

The application discloses a kind of cold-rolled roller processing methods suitable for high surface quality titanium alloy sheet, belong to material processing and roller manufacturing technical field, adopt laser texturing+ laser strengthening composite surface modification technology, and the performance of roller is promoted in combination with basic strengthening and interface regulation.Basic strengthening adopts nano-enhanced composite working layer deposition and magnetic field assisted multi-stage cryogenic treatment;Surface modification is through the composite design of "laser strengthening+ bionic laser texturing structure", with multiple groups of gradient coating;Interface regulation introduces low-temperature diffusion annealing.The method of the application makes the hardness of roller working layer reach 58-62HRC, impact toughness ≥17J / cm², coating bonding strength ≥95MPa, stick roll defect rate ≤3%, rolling pass life is improved by more than 55%, suitable for TC4-DT, Ti-6Al-4V ELI and other titanium alloy sheet cold rolling process in severe requirements, and has the potential to replace traditional chrome plating process.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of material processing and roll manufacturing, and particularly relates to a cold rolling roll processing method suitable for high-surface-quality titanium alloy sheet. BACKGROUND

[0002] High-strength and high-toughness titanium alloy sheet is widely used in high-end fields such as aerospace and medical devices due to its excellent mechanical properties. However, this type of material has high deformation resistance (yield strength ≥ 860 MPa) and low thermal conductivity (only 1 / 5 of 45 steel), and the surface is highly active, which leads to three major technical bottlenecks in the cold rolling process: first, the performance matching contradiction, traditional single strengthening process cannot balance hardness and toughness, high hardness roll is prone to edge collapse failure, and high toughness roll has insufficient wear resistance; second, the surface failure mechanism is complex, adhesion wear is easily generated between the roll and the titanium alloy during rolling, and the thermal fatigue effect caused by temperature fluctuation will aggravate the surface crack initiation; third, the process synergy is poor, deep cryogenic treatment easily introduces residual tensile stress (usually ≥ 300 MPa), and the coating technology has insufficient bonding strength (usually ≤ 80 MPa) due to thermal expansion mismatch.

[0003] In the existing roll processing technology, the composite working layer is mostly deposited using single-component welding material, and the anti-adhesion performance control effect is limited; the deep cryogenic process is mostly in a single-stage cooling mode, and the stress relief is insufficient; the surface modification technology only focuses on hardness improvement or ignores the interface bonding state between the coating and the substrate.

[0004] Therefore, there is an urgent need to develop a multi-process synergistic roll processing method to solve the above technical bottlenecks and provide technical support for stable rolling of high-surface-quality titanium alloy sheet. SUMMARY

[0005] In view of the above technical problems, the application provides a cold rolling roll processing method suitable for high-surface-quality titanium alloy sheet.

[0006] To achieve the above purpose, the application provides the following technical scheme:

[0007] A cold rolling roll processing method suitable for high-surface-quality titanium alloy sheet, comprising the following steps:

[0008] (1) ultrasonic flaw detection and vacuum sandblasting pretreatment are performed on the roll spindle, and a nano-enhanced composite working layer containing nano-CeO2 is deposited on the surface of the roll spindle to form a defect-free thick working layer;

[0009] (2) multi-stage deep cryogenic treatment and composite tempering are performed under the assistance of a magnetic field to greatly reduce residual stress and promote martensite transformation, thereby improving overall strength and toughness;

[0010] (3) Strengthen the surface by high-energy laser, and construct bionic laser micro-nano texture (i.e. bionic pit-groove composite texture) by femtosecond laser to optimize the surface friction and lubrication performance;

[0011] (4) Prepare TiN transition layer, multi-component gradient coating in sequence, and perform segmented plasma oxidation to form a compact wear-resistant composite surface system;

[0012] (5) Finally, perform low-temperature vacuum diffusion annealing to promote element interdiffusion between the coating and the substrate, enhance the interface bonding strength, and obtain a cold-rolled roller with high surface quality, high strength and high toughness.

[0013] Optionally, the nano-enhanced composite working layer containing nano CeO2 includes the following components in terms of mass percentage:

[0014] C 0.18-0.22%, Mn 1.0-1.6%, Si 0.2-0.35%, Cr 0.3-0.5%, Mo 0.25-0.5%, CeO20.05-0.1%, P≤0.03%, S≤0.03%, and the balance being Fe;

[0015] The particle size of the CeO2 is 50-80 nm.

[0016] Optionally, the conditions of the magnetic field assisted multi-stage cryogenic treatment and composite tempering are as follows:

[0017] Under a direct current magnetic field of 0.2-0.3 T, sequentially cool to -50°C, -100°C and -196°C and hold respectively, and then temper at 200°C for 2 h;

[0018] Then, under a direct current magnetic field of 0.1-0.2 T, cool to -196°C, hold at this temperature for 4 h, and then temper at 250°C for 2 h.

[0019] Further, the cooling rate to -50°C and -100°C is ≤5°C / min, and the holding time is 2 h each;

[0020] The cooling rate to -196°C is ≤3°C / min; and the holding time is 2 h.

[0021] Optionally, the conditions of the high-energy laser are as follows: wavelength 1064 nm, power 1500-1800 W, scanning speed 700-900 mm / min, spot size 5×10 mm, heating zone temperature 950-1050°C, and 1.5-2 mm deep strengthening layer formed after self-cooling quenching.

[0022] Optionally, the conditions of the femtosecond laser are as follows: wavelength 1064 nm, pulse width 50 fs, energy density 1-2 J / cm 2 .

[0023] Optionally, the TiN transition layer is prepared by magnetron sputtering, and the preparation conditions are as follows: sputtering power 800-1000 W, argon flow rate 20 sccm, thickness 0.2-0.3 μm, and coating bonding strength ≥ 95 MPa.

[0024] Optionally, the multi-component gradient hard coating layer comprises, from inside to outside, a bottom layer, a middle layer and a surface layer.

[0025] In addition to the Ni60A nickel-based alloy, the bottom layer contains 10 wt% WC and 5 wt% TiC, the middle layer contains 25-30 wt% WC and 7-8 wt% TiC, and the surface layer contains 45-50 wt% WC and 9-10 wt% TiC, wherein the thickness of each layer is 0.8-1 mm.

[0026] Further, the multi-component gradient hard coating layer is deposited by layer-by-layer laser cladding, and the conditions of the laser cladding are as follows:

[0027] Power 2800-3200 W, powder feeding amount 18-22 g / min, and scanning speed 300-400 mm / min.

[0028] Optionally, the conditions of the segmented plasma oxidation are as follows: first, heat preservation at 300℃ for 10-12 minutes, and then the mixed gas of argon and oxygen is introduced, with a volume ratio of 9:1 and a total flow rate of 50 sccm.

[0029] Subsequently, heat to 500℃ and heat preservation for 18-20 minutes, and then adjust the volume ratio of argon and oxygen to 7:3 to form an Al2O3-TiO2 composite oxide layer with a thickness of 1-2 μm (wherein Al comes from the Ni60A nickel-based alloy (conventional Ni60A contains 3-5% Al), and Ti comes from the TiN transition layer and the TiC reinforcing phase).

[0030] Optionally, the conditions of the low-temperature vacuum diffusion annealing are as follows: under the condition of a vacuum degree ≤ 1×10 -3 Pa, heat preservation at 430-470℃ for 3-5 hours to make the element diffusion distance between the coating and the substrate reach 1.5-2.0 μm.

[0031] Compared with the prior art, the present application has the following advantages and technical effects:

[0032] (1) The environmental friendliness is significantly improved: the laser texturing + laser strengthening composite technology of the present application is expected to replace the chrome plating process, avoid the emission of hexavalent chromium ions, meet the GB21900-2020 "Electroplating Pollutant Discharge Standard", and solve the environmental pollution and wastewater treatment problems of traditional chrome plating.

[0033] (2) Cryogenic treatment effect optimization: The magnetic field assisted multi-stage cryogenic treatment defined in the application promotes martensite nucleation through 0.2-0.3T direct current magnetic field, slows down thermal stress through gradient cooling rate (≤5℃ / min), further refines the structure through secondary cryogenic treatment and tempering, reduces residual stress to ≤220MPa (≥300MPa in Comparative Example 1), increases martensite transformation rate to above 92% (martensite transformation rate is 75-80% in Comparative Example 1), and reduces plastic deformation of the roller under cyclic load by above 40%.

[0034] (3) Surface functional property enhancement: The synergistic design of the "pit-groove" composite biomimetic laser micro-nano texture (diameter 5-10μm, width 20μm) and Ni60A-WC-TiC multi-component gradient coating realizes the functional matching of anti-adhesion and wear resistance; wherein, the "pit-groove" composite biomimetic texture (coverage rate 30-40%) can store lubricating oil, so that the friction coefficient is reduced to 0.15-0.20 (0.3-0.35 in Comparative Example 1), and the sticking defect rate is ≤3% (≥15% in Comparative Example 1).

[0035] (4) The application adopts interface regulation technology of TiN transition layer sputtering and low temperature diffusion annealing, eliminates stress concentration between the coating and the substrate through element gradient diffusion; the synergistic effect of TiN transition layer and multi-component gradient coating makes the bonding strength ≥95MPa (generally ≤50MPa for existing treatment methods), the thermal shock resistance ΔT ≥350℃, and the coating peeling failure period is prolonged by 2-3 times. Among them, the TiN transition layer (0.2-0.3μm) relieves the thermal expansion mismatch between the coating and the substrate, the multi-component gradient coating (WC-TiC content gradient distribution) makes the bonding strength increase to ≥95MPa (60-75MPa in Comparative Example 1), and the coating peeling failure period is prolonged by 2-3 times.

[0036] (5) Process is efficient and reliable: The application discloses a roller treatment method with multiple process synergies, which can be industrialized, and the rolling pass life is improved by above 55% compared with chromium plated roller. BRIEF DESCRIPTION OF DRAWINGS

[0037] The accompanying drawings, which form a part of this application, are used to provide a further understanding of the application and are incorporated in and constitute a part of this application. Exemplary embodiments of the present application and its description are used to explain the application, and do not constitute an improper limitation on the application. In the drawings:

[0038] Figure 1 It is a cold rolling roller treatment process flow chart of the application;

[0039] Figure 2 It is a roller cross section structure schematic diagram of the application;

[0040] Figure 3 It is a local enlarged schematic diagram of the biomimetic laser micro-nano texture of Example 1 of the application. Detailed Implementation

[0041] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0042] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0043] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0044] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0045] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0046] This invention discloses a method for processing cold rolling rolls suitable for high-strength and high-toughness titanium alloy thin plates with high surface quality, comprising the following steps:

[0047] Step 1: Spindle pretreatment → Nano-reinforced composite layer deposition;

[0048] Step 2: Magnetic field-assisted multi-stage cryogenic treatment → composite tempering;

[0049] Step 3: Laser strengthening → Bionic laser wool-like texture processing;

[0050] Step 4: TiN transition layer sputtering → multi-component gradient coating cladding → segmented plasma oxidation;

[0051] Step 5: Low-temperature diffusion annealing.

[0052] In some optional embodiments, in step 1, the chemical composition (mass fraction) of the welding material used for depositing the nano-reinforced composite working layer is: C 0.18-0.22%, Mn 1.0-1.6%, Si 0.2-0.35%, Cr 0.3-0.5%, Mo 0.25-0.5%, CeO2 0.05-0.1%, P≤0.03%, S≤0.03%, wherein the CeO2 particle size is 50-80nm.

[0053] Preferably, the nano-reinforced welding material is prepared by mechanical alloying, with a ball milling time of 8-10 hours, a ball-to-material ratio of 10:1, and a rotation speed of 200-300 r / min.

[0054] In some optional embodiments, in step 2, the magnetic field-assisted multi-stage cryogenic process is as follows: room temperature → -50℃ (≤5℃ / min, hold for 2h) → -100℃ (≤5℃ / min, hold for 2h) → -196℃ (≤3℃ / min, hold for 6h), with a DC magnetic field of 0.2-0.3T applied; the secondary cryogenic process is -196℃ × 4h, with a DC magnetic field of 0.1-0.2T applied.

[0055] In some optional embodiments, in step 2, the composite tempering process is tempering at 200±5℃ for 2 hours after the first deep cryogenic treatment, and tempering at 250±5℃ for 2 hours after the second deep cryogenic treatment, with a heating rate of ≤3℃ / min.

[0056] In some alternative embodiments, the laser strengthening in step 3 uses a semiconductor laser, and the laser strengthening conditions are as follows:

[0057] Power 1500-1800W, scanning speed 700-900mm / min, spot size 5×10mm, heating zone temperature 950-1050℃, reinforcement layer depth 1.5-2mm, surface hardness 62-65HRC.

[0058] Preferably, the martensite grain size of the surface layer of the laser-strengthened roll is ≤5μm, and the residual compressive stress is ≥-150MPa (meaning compressive stress, which can effectively inhibit the initiation of fatigue cracks).

[0059] In some optional embodiments, in step 3, the biomimetic laser-textured texture is a "pit-groove" composite texture, with pits having a diameter of 5-10 μm and a depth of 3-5 μm, and grooves having a width of 20 μm and a depth of 4 μm, and a distribution density of 60-80 pits / mm. 2 The process was performed using a femtosecond laser under the following conditions: wavelength 1064nm, pulse width 50fs, and energy density 1-2J / cm². 2 .

[0060] Preferably, the coefficient of friction of the laser-textured fabric is 0.15-0.20, and the roller sticking defect rate is ≤3%.

[0061] In some optional embodiments, in step 4, the TiN transition layer is prepared by magnetron sputtering with a sputtering power of 800-1000W, an argon flow rate of 20sccm, a thickness of 0.2-0.3μm, and a coating bonding strength ≥95MPa.

[0062] In some optional embodiments, the multi-component gradient coating is distributed in a gradient as follows: bottom layer (WC 10% + TiC 5%, with the balance being Ni60A as the matrix phase), middle layer (WC 30% + TiC 8%, with the balance being Ni60A as the matrix phase), and top layer (WC 50% + TiC 10%, with the balance being Ni60A as the matrix phase), with each layer having a thickness of 0.8-1 mm;

[0063] The above-mentioned multi-component gradient coating was prepared by laser cladding, with the laser cladding parameters being a power of 2800-3200W, a powder feed rate of 18-22g / min, and a scanning speed of 300-400mm / min.

[0064] Preferably, the multi-component gradient coating has a thermal shock resistance ΔT≥350℃ and no cracks after 10 thermal cycles (25℃→350℃→25℃).

[0065] In some optional embodiments, in step 4, the segmented plasma oxidation process is 300℃×10min (Ar:O2=9:1)→500℃×20min (Ar:O2=7:3) to form a 1-2μm Al2O3-TiO2 composite oxide layer.

[0066] In some optional embodiments, in step 5, the low-temperature diffusion annealing parameters are 450±10℃×4h, the heating rate is ≤5℃ / min, and the diffusion distance between the coating and the matrix elements after annealing is ≥1.5μm.

[0067] In some optional embodiments, the cold rolling roll treatment method disclosed in this invention achieves an overall performance improvement of the roll through the synergistic effect of basic strengthening, laser composite modification, and interface control. The specific steps are as follows:

[0068] 1. Basic strengthening technology: Optimization of roll matrix properties

[0069] (1) Nano-reinforced composite working layer deposition process

[0070] Using 55Cr medium-carbon alloy forged steel as the main roll shaft (laboratory specifications φ100-200mm×300-500mm), after ultrasonic testing (JB / T5000.15-2007 Class I standard), the surface was roughened using a vacuum sandblasting box (Ra=5-8μm); submerged arc welding was performed using nano-reinforced low-alloy welding materials. The chemical composition (mass fraction) of the welding materials was C 0.18-0.22%, Mn 1.0-1.6%, Si 0.2-0.35%, Cr 0.3-0.5%, Mo 0.25-0.5%, CeO2 0.05-0.1% (nano CeO2 particle size 50-80nm), P≤0.03%, S≤0.03% (composition testing according to GB / T). (4336-2016); During the cladding process, an infrared temperature measurement system is used to control the interlayer temperature at 200-250℃, and the cladding thickness is 10-15mm; Nano CeO2 refines the grains by pinning grain boundaries, thereby improving the toughness of the working layer.

[0071] (2) Magnetic field-assisted multi-stage cryogenic process

[0072] The melt-treated rolls were placed in a magnetically controlled cryogenic chamber and subjected to a 0.2-0.3T DC magnetic field for gradient cooling: ① room temperature → -50℃ (≤5℃ / min, hold for 2h) → -100℃ (≤5℃ / min, hold for 2h) → -196℃ (≤3℃ / min, hold for 6h); after the first cryogenic treatment, the temperature was increased to 200±5℃ at ≤3℃ / min and held for 2h for tempering; second cryogenic treatment: -196℃×4h (applying a 0.1-0.2T magnetic field) → 250±5℃×2h for tempering; the residual stress after treatment was ≤220MPa (X-ray diffraction method GB / T7704-2017), and the martensite transformation rate was increased to over 92% (XRD detection GB / T 23414-2009).

[0073] 2. Laser composite modification technology: synergistic improvement of surface properties

[0074] (1) Laser strengthening process

[0075] The cryogenically treated rolls are laser hardened using a semiconductor laser: power 1500-1800W, scanning speed 700-900mm / min, spot size 5×10mm, heating zone temperature 950-1050℃. Through rapid laser heating and cooling, a fine-grained martensite structure is formed, the surface hardness is increased to 62-65HRC, and the depth of the reinforced layer is 1.5-2mm.

[0076] (2) Laser-assisted texturing process

[0077] After laser enhancement, a femtosecond laser is used to process the biomimetic wool-like texture: wavelength 1064nm, pulse width 50fs, energy density 1-2J / cm².2 Processing a "pit-groove" composite structure (pit diameter 5-10μm, depth 3-5μm, groove width 20μm, depth 4μm), with a texture distribution density of 60-80 pits / mm. 2 (SEM observation GB / T 16594-2008); Before the texture processing, the surface is cleaned with alcohol using a laboratory ultrasonic cleaner to remove oil stains; This woolen texture can store lubricating oil and destroy the adhesive interface, reducing the coefficient of friction to 0.15-0.20, replacing the friction reduction and wear resistance function of the chromium plating layer, and without chromium pollution.

[0078] 3. Interface control and coating technology: Performance stability optimization

[0079] (1) Sputtering of TiN transition layer

[0080] A TiN transition layer was then prepared using a magnetron sputtering system: sputtering power 800-1000W, argon flow rate 20 sccm, and thickness 0.2-0.3 μm. The TiN layer exhibits good compatibility with both the substrate and the coating, effectively mitigating thermal expansion mismatch and enhancing the bonding strength of the coating.

[0081] (2) Multi-component gradient coating and low-temperature diffusion

[0082] Laser cladding uses a fiber laser to clad a Ni60A-WC-TiC gradient coating: bottom layer (WC 10%+TiC 5%), middle layer (WC 30%+TiC 8%), and top layer (WC 50%+TiC 10%), with each layer having a thickness of 0.8-1mm. The cladding parameters are: power 2800-3200W, powder feed rate 18-22g / min, and scanning speed 300-400mm / min. Subsequently, segmented plasma oxidation is performed: 300℃×10min (Ar:O2=9:1) → 500℃×20min (Ar:O2=7:3) to form a 1-2μm Al2O3-TiO2 composite oxide layer (coating bonding strength ≥100MPa, GB / T 8642-2002). Finally, diffusion annealing was performed in a laboratory vacuum annealing furnace at 450±10℃ for 4 hours, with a heating rate ≤5℃ / min and an element diffusion distance ≥1.5μm.

[0083] The rolling pass life of the processing method of this invention is increased by more than 55% compared with the traditional roll processing process.

[0084] In summary, this invention proposes a composite modification system of "laser-strengthened undercoating - laser texturing functionalization". Laser strengthening improves surface hardness and wear resistance through fine grain strengthening, while laser texturing reduces friction and prevents adhesion through texture design. The two work together to solve the performance bottleneck of single laser treatment. Combined with nano-reinforcement, magnetic field deep cooling and gradient coating technology, a multi-process synergistic roll processing solution is formed to meet the cold rolling requirements of high-strength and high-toughness titanium alloy thin plates.

[0085] Unless otherwise specified, "room temperature" in this invention refers to 20-30℃.

[0086] All raw materials used in this invention were purchased from the market.

[0087] The English abbreviations and special symbols mentioned in this invention are explained as follows:

[0088] CeO2: Cerium dioxide, a nano-reinforcing phase material;

[0089] XRD: X-ray diffraction, used to detect martensitic transformation rate and for phase analysis;

[0090] EDS: Energy Dispersive X-ray spectroscopy, used for elemental distribution and diffusion distance detection;

[0091] HVOF: High-speed flame spraying, a coating preparation method in the existing technology;

[0092] Ra: Surface roughness parameter, characterizing the micro-irregularity of the surface;

[0093] WC: Tungsten carbide, coating reinforcement phase;

[0094] TiC: Titanium carbide, a coating-synergistic reinforcing phase;

[0095] TiN: Titanium nitride, a coating transition layer material.

[0096] The technical solution of the present invention will be further illustrated by the following embodiments.

[0097] Example 1: Processing TC4-DT aerospace structural sheet (2mm thickness) with φ500mm×1200mm rolls

[0098] A method for processing cold rolling rolls suitable for high-strength, high-toughness titanium alloy thin sheets with high surface quality includes the following steps:

[0099] Step 1: Spindle pretreatment and nano-reinforced cladding:

[0100] A φ500mm×1200mm 55Cr medium carbon alloy forged steel spindle (chemical composition: C 0.55%, Si 0.28%, Mn 0.85%, Cr 1.52%, conforming to GB / T3077-2015) was selected. An ultrasonic flaw detector (model CTS-2000, probe frequency 2.5MHz) was used to inspect it according to the JB / T5000.15-2007 Class I standard to ensure no internal defects ≥φ2mm were present. Surface roughening was performed using a vacuum sandblasting device (model KL-800, vacuum degree -0.09MPa). The sandblasting medium was brown corundum (80 mesh, hardness 9.0 Mohs), the sandblasting pressure was 0.6MPa, and the scanning speed was 50mm / s. The surface roughness after treatment was Ra=6.5μm (roughness meter TR200, measuring length 4mm, average of 5 points).

[0101] Preparation of nano-reinforced welding material: Industrially pure CeO2 powder (particle size 60nm, purity 99.9%, specific surface area 32m²) was used. 2 CeO2 powder (C=0.20%, Mn=1.4%, Si=0.3%, Cr=0.4%, Mo=0.4%, P=0.025%, S=0.022%) was mixed with nano-reinforced composite working powder (composition: C=0.20%, Mn=1.4%, Si=0.3%, Cr=0.4%, Mo=0.4%, P=0.025%, S=0.022%), wherein the mass percentage of CeO2 powder in the welding material was 0.08%. The mixture was placed in a planetary ball mill (model QM-3SP4, agate ball milling jar) with a ball-to-material ratio of 10:1, a rotation speed of 300 r / min, and a ball milling time of 9 h (with a 30 min stop every 2 h, and a temperature control of ≤50℃). The particle size distribution of the welding material was detected by a Mastersizer3000 laser particle size analyzer, and the particle size distribution D50 was 75 nm.

[0102] Submerged arc automatic deposition: The welding machine model MZ-1000 (DC reverse polarity) is used, with a welding current of 600A, a voltage of 32V, a welding speed of 300mm / min, and a deposition efficiency of 8kg / h. During the deposition process, the interpass temperature is controlled at 230℃ by a dual infrared thermometer (TI 400, accuracy ±2℃). The deposition thickness of each weld layer is 3mm, and the total deposition thickness is 45mm. After deposition, the weld layer is naturally cooled to room temperature, and the microstructure of the weld layer is observed to be free of cracks and pores by a metallographic microscope DMi8.

[0103] Step 2: Magnetic field-assisted multi-stage cryogenics and composite tempering

[0104] The melt-coated rolls were placed in a magnetically controlled cryogenic chamber (model DWC-196-600, temperature control accuracy ±1℃). A 0.25T DC magnetic field (magnetic field uniformity 92%) was applied by an electromagnet, and the gradient cooling program was as follows: room temperature → -50℃ (cooling rate 4℃ / min, holding for 2h) → -100℃ (cooling rate 4℃ / min, holding for 2h) → -196℃ (cooling rate 3℃ / min, holding for 6h). Liquid nitrogen was used as the refrigerant. After the first cryogenic cooling, the temperature was raised to room temperature at 3℃ / min, and then placed in a box-type resistance furnace (SX2-12-10, temperature control accuracy ±5℃) for tempering at 200℃ for 2h (heating rate 5℃ / min, air cooling).

[0105] Secondary cryogenic treatment: The rolls were placed in a magnetically controlled cryogenic chamber again, a 0.15T DC magnetic field was applied, and the temperature was maintained at -196℃ for 4 hours, followed by tempering at 250℃ for 2 hours. After treatment, the residual stress was measured to be 210MPa using an X-ray diffractometer (X'PertPro, Cu target Kα rays) according to GB / T7704-2017, and the martensite transformation rate was measured to be 93% according to GB / T23414-2009.

[0106] Step 3: Laser Enhancement and Biomimetic Fur-like Texture

[0107] One-time laser strengthening: A semiconductor laser (model RFL-C1500, wavelength 1064nm) was used, with a power of 1600W, a scanning speed of 800mm / min, a spot size of 5×10mm (rectangular spot), and a heating zone temperature of 1000℃ (monitored by an infrared thermal imager Ti400). After self-cooling quenching, a 1.8mm deep strengthening layer was formed. The hardness of the strengthening layer was measured to be 62HRC by a microhardness tester HV-1000 (load 200g), the grain size was 5μm (EBSD test, GB / T25945-2010), and the residual stress was -120MPa.

[0108] Bionic laser texturing: After laser strengthening, ultrasonic cleaning with alcohol is performed (equipment KQ-300V, power 300W, time 15min). Processing is then carried out using a femtosecond laser (model SpitfireAce, pulse width 50fs, repetition frequency 1kHz) at a wavelength of 1064nm, energy density of 1.8J / cm², and scanning step size of 2μm. A "pit-groove" composite texture is fabricated: pits with a diameter of 8μm and a depth of 4μm, grooves with a width of 20μm and a depth of 4μm, and a texture distribution density of 70 pits / mm. 2 , with a coverage of 35% (scanning electron microscope SU8010, accelerating voltage 15kV, observing 5 random areas).

[0109] Step 4: Coating Preparation

[0110] TiN transition layer sputtering: A magnetron sputtering system (JGP-450, vacuum degree 5×10⁻⁶) was used. -4The target material was 99.95% pure Ti, the sputtering power was 900W, the argon flow rate was 20sccm, the deposition time was 30min, and the coating thickness was 0.25μm (film thickness gauge F20, accuracy ±1nm).

[0111] Multi-component gradient coating cladding: Ni60A-WC-TiC mixed powder was prepared according to the following formula: bottom layer (WC 10%+TiC 5%), middle layer (WC 30%+TiC 8%), and top layer (WC 50%+TiC 10%). The Ni60A powder conformed to GB / T14992-2005; WC purity was 99.5% and particle size was 2μm; TiC purity was 99.6% and particle size was 2μm. The powder was mixed for 5 hours using a planetary powder mixer XQM-4 (speed 250r / min). The cladding was performed using a fiber laser YLS-4000 with a power of 3000W, a powder feed rate of 20g / min, a scanning speed of 350mm / min, an Ar protective gas flow rate of 18L / min, and a layer thickness of 0.9mm.

[0112] Segmented plasma oxidation: In a DPL-600 plasma oxidation furnace, 300℃×10min (Ar∶O2=9∶1, total flow rate 50sccm) → 500℃×20min (Ar∶O2=7∶3) to form a 1.5μm Al2O3-TiO2 composite oxide layer (components analyzed by an ESCALAB250Xi X-ray photoelectron spectroscopy instrument).

[0113] Step 5: Low-temperature diffusion annealing

[0114] Low-temperature diffusion annealing: in a vacuum annealing furnace ZKL-60 (vacuum degree 1×10⁻⁶) -3 In a furnace, the temperature was increased to 450℃ at 4℃ / min, held for 4h, and then cooled to room temperature. The diffusion distance between the coating and the substrate elements was detected by EDS line scanning INCAX-Max, which showed a value of 1.8μm.

[0115] Performance Testing and Application: The rolls were installed on a 20-roll cold rolling mill HC-20 to roll TC4-DT thin plates (2mm thick). Process parameters: rolling force 3500kN, rolling speed 15m / min, pass reduction 15%. After 5200 passes, the wear of the working layer was measured to be 0.8mm using a laser profilometer LK-G80, the surface roughness tester Ra=0.3μm using a TR200, the roll sticking defect rate was 2.5% using visual inspection and CCD, and the thickness deviation was measured to be ±0.018mm using a micrometer (accuracy ±1μm). This meets the GB / T3621-2022 standard for aerospace titanium plates. Specific performance data are shown in Table 1.

[0116] Example 2: φ300mm×800mm roll-processed Ti-6Al-4V ELI thin plate (1mm thickness) for medical implants

[0117] A method for processing cold rolling rolls suitable for high-strength and high-toughness titanium alloy thin sheets with high surface quality, the specific steps of which are as follows:

[0118] Step 1: Spindle pretreatment and nano-reinforced cladding

[0119] A φ300mm×800mm 55Cr medium carbon alloy forged steel spindle was selected (chemical composition: C 0.53%, Si 0.26%, Mn 0.82%, Cr 1.48%, conforming to GB / T 3077-2015), with P=0.023% and S=0.021%, meeting the low impurity requirements for medical grade. An ultrasonic flaw detector (model CTS-9006, probe frequency 5MHz) was used to inspect the spindle according to JB / T5000.15-2007 Class I standard to ensure no internal defects ≥φ1.5mm. Surface roughening was performed using a vacuum sandblasting device (model KL-800, vacuum degree -0.09MPa), with medical-grade white corundum (120...). The surface roughness was measured using a roughness tester (TR200, measuring length 3mm, average of 5 points) with an impurity content of ≤0.1% and sterilized by high-pressure steam at 121℃. The surface roughness was Ra=5.2μm. Then, the surface was ultrasonically cleaned with 95% medical alcohol (KQ-300V equipment, power 300W, time 15min) to remove residual sand particles. The surface was then dried at 60℃ for later use.

[0120] Preparation of Nano-Reinforced Welding Material: Medical-grade industrial pure CeO2 powder (particle size 60nm, purity 99.99%, meeting the safety requirements of GB / T 35812-2023 Medical Nanomaterials, specific surface area 30m² / g) was mixed with nano-reinforced composite working powder (composition: C 0.19%, Mn 1.2%, Si 0.25%, Cr 0.4%, Mo 0.3%, P=0.018%, S=0.017%, balance Fe) at a mass ratio, wherein the mass percentage of nano-CeO2 in the final welding material was 0.06%; the mixture was placed in a planetary ball mill (model QM-3SP4, agate ball mill jar to avoid metal contamination), with a ball-to-material ratio of 8:1, a rotation speed of 280r / min, and a ball milling time of 8h (with a 30min stop every 2h, temperature controlled ≤50℃), and a Mastersizer 3000 laser particle size analyzer was used. The particle size distribution of the welding material was measured to be D50=72nm to ensure uniform dispersion of nanoparticles.

[0121] Manual arc welding deposition: A welding machine model ZX7-500 (DC reverse polarity) was used, with a welding current of 200A, a voltage of 24V, a welding speed of 250mm / min, and a deposition efficiency of 3.5kg / h. During the deposition process, the interpass temperature was controlled at 210℃ using a dual infrared thermometer (TI 400, accuracy ±2℃). The deposition thickness of each weld layer was 2.5mm, and the total deposition thickness was 35mm. After each weld layer was deposited, compressed air (filtration accuracy 0.1μm) was used to blow away the surface oxide scale to avoid impurity residue. After deposition, the weld layer was allowed to cool naturally to room temperature. The weld layer structure was observed using a metallographic microscope DMi8. No defects such as cracks or pores were found. The weld layer impurities were detected using a direct-reading spectrometer SPECTROMAXx, which met the YY / T 0662-2023 standard for titanium and titanium alloy plates for surgical implants.

[0122] Step 2: Magnetic field-assisted multi-stage cryogenics and composite tempering

[0123] The melt-coated rolls are placed in a magnetically controlled cryogenic chamber (model DWC-196-300, temperature control accuracy ±1℃, volume suitable for small rolls). A 0.22T DC magnetic field (magnetic field uniformity 91%) is applied by an electromagnet, and the gradient cooling program is as follows: room temperature → -50℃ (cooling rate 4℃ / min, holding for 2h) → -100℃ (cooling rate 4℃ / min, holding for 2h) → -196℃ (cooling rate 3℃ / min, holding for 5h). The refrigerant is high-purity liquid nitrogen (purity ≥99.999%). After the first cryogenic cooling, the temperature is raised to room temperature at 3℃ / min, and then placed in a box-type resistance furnace (SX2-10-10, temperature control accuracy ±5℃) for tempering at 200℃ for 2h (heating rate 5℃ / min, air cooling to room temperature).

[0124] Secondary cryogenic treatment: The rolls were placed in a magnetically controlled cryogenic chamber again, and a DC magnetic field of 0.13T was applied. The temperature was held at -196℃ for 4 hours, and then tempered (air-cooled) by increasing the temperature to 250℃ for 2 hours at a rate of 3℃ / min. After treatment, the residual stress was measured to be 205MPa using an X-ray diffractometer (X'PertPro, Cu target Kα rays) according to GB / T 7704-2017, and the martensite transformation rate was measured to be 92.5% according to GB / T 23414-2009.

[0125] Step 3: Laser Enhancement and Biomimetic Fur-like Texture

[0126] One-time laser strengthening: A semiconductor laser (model RFL-C1500, wavelength 1064nm) was used, with a power of 1500W, a scanning speed of 750mm / min, a spot size of 5×8mm (rectangular spot), and a heating zone temperature of 980℃ (monitored by an infrared thermal imager Ti400). After self-cooling quenching, a 1.6mm deep strengthening layer was formed. The hardness of the strengthening layer was measured to be 60HRC using a microhardness tester HV-1000 (load 200g, holding pressure 15s). The grain size was 5.5μm according to EBSD testing (GB / T 25945-2010), and the residual stress was -130MPa (X-ray diffraction test, conforming to GB / T 7704-2017, which is residual compressive stress, meeting the preferred range ≥-150MPa).

[0127] Bionic laser texturing: After laser strengthening, the surface oxide film was removed by ultrasonic cleaning with 95% medical alcohol (equipment KQ-300V, power 300W, time 10min); a femtosecond laser (model Spitfire Ace, pulse width 50fs, repetition frequency 1kHz) was used for processing, with a wavelength of 1064nm, energy density of 1.6J / cm², and scanning step size of 2μm; a "pit-groove" composite texture was processed: pit diameter 6μm, depth 3.5μm, groove width 18μm, depth 3.8μm, texture distribution density 80 / mm², coverage 32% (scanning electron microscope SU8010, accelerating voltage 10kV, observation of 5 random areas); the surface friction coefficient of the texture was measured to be 0.17 using a UMT-3 tribometer.

[0128] Step 4: Coating Preparation

[0129] TiN transition layer sputtering: A magnetron sputtering system (JGP-450, vacuum degree 5×10⁻⁶) was used. -4 The sputtering power was 950W, the argon flow rate was 20sccm (purity 99.999%), the deposition time was 35min, and the coating thickness was 0.3μm as measured by an F20 film thickness gauge (accuracy ±1nm). The coating bonding strength was 95MPa as measured by a WDW-100 tensile testing machine according to GB / T 8642-2002.

[0130] Multi-component gradient coating cladding: A mixed powder was prepared according to the following layers: bottom layer (Ni60A + 10wt% WC + 5wt% TiC), middle layer (Ni60A + 25wt% WC + 7wt% TiC), and top layer (Ni60A + 45wt% WC + 9wt% TiC). The Ni60A powder conformed to GB / T 14992-2005 and met medical-grade impurity requirements; WC purity was 99.5% with a particle size of 2μm; TiC purity was 99.6% with a particle size of 2μm. The powder was mixed in a planetary mixer XQM-4 for 5 hours (250 r / min, reversed every hour). A YLS-4000 fiber laser was used for cladding at a power of 2800W, a powder feed rate of 19 g / min, and a scanning speed of 320 mm / min. The protective gas flow rate is 18L / min (purity 99.999%), the thickness of each layer is 0.9mm, and there are no pores or cracks on the surface after cladding.

[0131] Segmented plasma oxidation: In a DPL-600 plasma oxidation furnace, the temperature was first held at 300℃ for 12 min, and a mixture of argon and oxygen (volume ratio 9:1, total flow rate 50 sccm, purity 99.999%) was introduced; then the temperature was raised to 500℃ and held for 18 min, and the volume ratio of argon to oxygen was adjusted to 7:3; after treatment, a 1.2 μm thick Al2O3-TiO2 composite oxide layer was formed (the composition was analyzed by an ESCALAB 250Xi X-ray photoelectron spectroscopy instrument, with Al element derived from Ni60A nickel-based alloy and Ti element derived from TiN transition layer and TiC reinforcing phase).

[0132] Step 5: Low-temperature diffusion annealing

[0133] The coated rolls are placed in a vacuum annealing furnace ZKL-60 (vacuum degree 1×10⁻⁶). -3 In the furnace, the temperature was increased to 440℃ at 4℃ / min and held for 4.5h. The furnace was then cooled to room temperature (cooling rate ≤5℃ / min). The diffusion distance between the coating and the substrate elements was 1.6μm, and the hardness gradient transition range was 48μm, with no obvious stress abrupt change, as detected by EDS line scanning INCAX-Max.

[0134] Performance Testing and Application: The rolls were installed on a 12-roll cold rolling mill (model HC-12) for rolling Ti-6Al-4V ELI thin plates (1mm thick) for medical implants. Rolling process parameters: rolling force 2000kN, rolling speed 10m / min, pass reduction 10%, medical-grade lubricating oil (meeting ISO 10993-5 biocompatibility requirements) was used during rolling. After 4800 passes, the working layer wear was measured at 0.6mm using a laser profilometer (LK-G80), the surface roughness Ra of the thin plate was measured at 0.18μm using a laser confocal microscope (LSM700), the roll sticking defect rate was visually inspected (1.8%) using a CCD, and the thickness deviation was measured at ±0.015mm using a micrometer (accuracy ±1μm). Cytotoxicity testing was performed according to ISO 10993-5, and the L929 cell survival rate was 96%, conforming to YY / T 0662-2023. Standards for titanium plates used in surgical implants, applicable to the manufacture of medical implants. Specific performance data are shown in Table 1.

[0135] Comparative Example 1

[0136] A roll processing technology consisting of "composite working layer deposition + single-stage cryogenic treatment + single ceramic coating" comprises the following steps:

[0137] Using 55Cr medium carbon alloy forged steel as the main shaft of the roll, after roughening by ordinary sandblasting (Ra=8-10μm), submerged arc welding is performed using a nano-reinforced composite working material (chemical composition: C 0.20-0.25%, Mn 1.2-1.8%, Si 0.3-0.4%, Cr 0.4-0.6%, P≤0.035%, S≤0.035%) without nano-reinforcing phase. During the welding process, the interpass temperature is controlled at 250-300℃ by a single infrared thermometer, and the weld thickness is 35-45mm. After welding, the material is quenched at 860-880℃ for 2h and tempered at 540-560℃ for 2h.

[0138] The cryogenic treatment adopts a single-stage cooling mode: the room temperature is directly reduced to -196℃ at a rate of 8-10℃ / min, held for 4-5 hours, then naturally heated to room temperature, and then tempered at 200-220℃ for 2 hours in a single process; after treatment, the martensite transformation rate is about 75-80% as detected by X-ray diffraction.

[0139] Surface modification employs a "laser quenching + single WC-Co coating" process: laser quenching parameters are power 1600-1800W and scanning speed 600-700mm / min, forming a 1.2-1.5mm hardened layer; the coating is prepared using high-velocity ultrasonic flame spraying (HVOF) to create a single-component WC-Co coating (88% WC content, 12% Co content), with a coating thickness of 2-3mm. Spraying parameters are kerosene flow rate 0.9L / h, oxygen flow rate 16m³ / h, and spraying distance 280-300mm; after coating preparation, no special interface control treatment is performed, only conventional annealing at 400℃ for 2h is carried out.

[0140] The process relationships are as follows: spindle pretreatment → composite working layer cladding and heat treatment → single-stage deep cryogenic tempering → laser quenching → HVOF spraying of WC-Co coating. No transition layer, biomimetic texture and multi-field coupling control links are set in the whole process.

[0141] The method in Comparative Example 1 has the following drawbacks:

[0142] (1) Poor mechanical property matching of the working layer: The existing welding materials do not contain nano CeO2 reinforcing phase, and cannot improve toughness through grain boundary refinement and dispersion strengthening. At the same time, there is no laser shock strengthening after deposition, and the grains are coarse (average grain size 15-20μm), resulting in a working layer hardness of only 55-58HRC and impact toughness ≤12J / cm. 2 It is difficult to simultaneously achieve the wear resistance and anti-chipping ability required for titanium alloy rolling. This is because it lacks the pinning grain boundary effect of nano-reinforcing phases and the dislocation multiplication and grain refinement effect of laser shock.

[0143] (2) Limited effect of cryogenic treatment: The single-stage rapid cooling cryogenic treatment is adopted without the assistance of magnetic field. On the one hand, the sudden temperature change easily introduces residual tensile stress of ≥300MPa. On the other hand, the promoting effect of magnetic field on martensitic phase transformation is not utilized, the martensitic transformation rate is only 75-80%, the structural stability is insufficient, and the roll is prone to plastic deformation under cyclic load.

[0144] (3) Insufficient synergy between surface anti-adhesion and wear resistance: Only single laser quenching is used, without biomimetic micro-nano texture design, poor surface oil storage capacity, friction coefficient as high as 0.3-0.35, and the defect rate of sticking to the roll during titanium alloy rolling is ≥15%; at the same time, there is no transition layer between the single WC-Co coating sprayed by HVOF and the substrate, and the mismatch of thermal expansion coefficients results in a bonding strength of only 60-75MPa, and the coating is prone to peeling failure under thermal cycling load.

[0145] (4) Lack of interfacial bonding and stress control: There is no interlayer vibration treatment during the welding process, and coarse columnar crystals and pores are easily formed at the fusion line. The interfacial bonding strength is only 350-400MPa. After the coating is prepared, only conventional annealing is performed, without low-temperature diffusion annealing. The diffusion distance of elements between the coating and the substrate is ≤0.5μm, and there is obvious stress concentration, which leads to microcracks on the surface of the roll after 3000-3500 rolling passes.

[0146] (5) Insufficient process stability: Comparative Example 1 did not specifically control the radial runout of the rolls, but only relied on subsequent machining correction, resulting in a final radial runout of the rolls ≥0.05mm. During rolling, it is easy to cause thickness deviation of titanium alloy thin plates (above ±0.05mm), which cannot meet the dimensional accuracy requirements of high surface quality thin plates.

[0147] Table 1

[0148] Performance indicators Example 1 (TC4-DT roll for aviation) Example 2 (Ti-6Al-4V ELI roll for medical) Comparative Example 1 (roll made by conventional process) Work layer hardness 62 HRC 60 HRC 55-58 HRC Impact toughness 17.5 J / cm2 18 J / cm2 ≤ 12 J / cm2 Residual stress after cryogenic treatment 210 MPa (tensile stress) 205 MPa (tensile stress) ≥ 300 MPa (tensile stress) Martensitic transformation rate 93% 92.50% 75-80% Coating bond strength 98 MPa 95 MPa 60-75 MPa Roll surface friction coefficient 0.18 0.17 0.3-0.35 Rolling pass life 5200 passes 4800 passes 3000-3500 passes Sheet roughness after rolling 0.3 μm 0.18 μm 0.4-0.6 μm Rolling defect rate during rolling 2.50% 1.80% 4-6%

[0149] As can be seen from Table 1, the embodiments of the present invention are significantly superior to traditional processes in terms of hardness, toughness, coating bonding strength and rolling life, and can precisely adjust parameters according to the needs of different scenarios such as aviation and medical care to meet differentiated performance requirements.

[0150] Figure 1 This is a flow chart of the cold rolling roll processing technology of the present invention; from Figure 1 As can be seen from the above, the core process steps and their sequence in this invention are as follows: 1- Spindle pretreatment (ultrasonic detection + vacuum sandblasting) → 2- Nano-reinforced composite working layer cladding → 3- Magnetic field-assisted multi-stage deep cooling → 4- Composite tempering → 5- Laser strengthening treatment → 6- Bionic laser micro-nano texturing → 7- TiN transition layer sputtering → 8- Multi-component gradient coating cladding → 9- Segmented plasma oxidation → 10- Low-temperature diffusion annealing.

[0151] Figure 2 This is a schematic diagram of the cross-sectional structure of the roll of the present invention; the diagram is a radial cross-sectional view of the roll, labeled from the inside out as follows: 1-55Cr main shaft substrate; 2-nano-reinforced composite working layer; 3-TiN transition layer; 4-multi-component gradient coating, wherein 4a-bottom layer (WC 10%+TiC 5%), 4b-middle layer (WC 30%+TiC 8%), 4c-top layer (WC 50%+TiC 10%); 5-Al2O3-TiO2 composite oxide layer (thickness 1-2μm).

[0152] Figure 3 This is a partially enlarged schematic diagram of the biomimetic laser micro / nano texture of Embodiment 1 of the present invention. The figure is a partially enlarged view of the working surface of the roll (magnification 5000x); a. hemispherical pit, b. strip groove. Figure 3The geometric features of the biomimetic texture are visually displayed, demonstrating the surface function regulation of the biomimetic laser micro / nano texture.

[0153] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for processing cold rolling rolls suitable for high surface quality titanium alloy thin plates, characterized in that, Includes the following steps: (1) The main shaft of the roll is subjected to ultrasonic testing and vacuum sandblasting pretreatment, and a nano-reinforced composite working layer containing nano CeO2 is fused onto its surface; The nano-reinforced composite working layer containing nano-CeO2 comprises the following components by mass percentage: C 0.18-0.22%, Mn 1.0-1.6%, Si 0.2-0.35%, Cr 0.3-0.5%, Mo 0.25-0.5%, CeO2 0.05-0.1%, P≤0.03%, S≤0.03%, balance Fe; (2) Perform magnetic field-assisted multi-stage cryogenic treatment and composite tempering, with the following specific conditions: Under a DC magnetic field of 0.2-0.3T, the temperature was successively lowered to -50℃, -100℃ and -196℃ and held at the temperature respectively, and then tempered at 200℃ for 2 hours; Then, under a DC magnetic field of 0.1-0.2T, the temperature is lowered to -196℃, held at this temperature for 4 hours, and then tempered at 250℃ for 2 hours. (3) Laser hardening of the surface is performed by high-energy laser, and biomimetic laser micro-nano texture is constructed using femtosecond laser; (4) A TiN transition layer and a multi-component gradient coating were prepared sequentially, and segmented plasma oxidation was performed to form an Al2O3-TiO2 composite oxide layer; The multi-component gradient coating is distributed in a gradient manner as follows: the bottom layer consists of 10 wt.% WC + 5 wt.% TiC, with the balance being Ni60A as the matrix phase; the middle layer consists of 30 wt.% WC + 8 wt.% TiC, with the balance being Ni60A as the matrix phase; and the top layer consists of 50 wt.% WC + 10 wt.% TiC, with the balance being Ni60A as the matrix phase. (5) Finally, perform low-temperature vacuum diffusion annealing.

2. The method for cold rolling roll processing suitable for high surface quality titanium alloy thin plates according to claim 1, characterized in that, The conditions for the high-energy laser are: wavelength 1064nm, power 1500-1800W, scanning speed 700-900mm / min, spot size 5×10mm, heating zone temperature 950-1050℃, and self-cooling quenching.

3. The method for processing cold rolling rolls suitable for high surface quality titanium alloy thin plates according to claim 1, characterized in that, The conditions for the femtosecond laser are: wavelength of 1064 nm, pulse width of 50 fs, and energy density of 1-2 J / cm². 2 .

4. The method for processing cold rolling rolls suitable for high surface quality titanium alloy thin plates according to claim 1, characterized in that, The TiN transition layer was prepared by magnetron sputtering under the following conditions: sputtering power of 800-1000W, argon flow rate of 20sccm, and thickness of 0.2-0.3μm.

5. The method for processing cold rolling rolls suitable for high surface quality titanium alloy thin plates according to claim 1, characterized in that, The multi-component gradient coating is deposited layer by layer by laser cladding, and the conditions for laser cladding are as follows: The power is 2800-3200W, the powder feeding rate is 18-22g / min, and the scanning speed is 300-400mm / min.

6. The method for cold rolling roll processing suitable for high surface quality titanium alloy thin plates according to claim 1, characterized in that, The conditions for the segmented plasma oxidation are as follows: First, keep the temperature at 300℃ for 10-12 minutes, then introduce a mixture of argon and oxygen at a volume ratio of 9:1, with a total flow rate of 50 sccm. Then raise the temperature to 500℃ and hold for 18-20 minutes, adjusting the volume ratio of argon to oxygen to 7:

3.

7. The method for cold rolling roll processing suitable for high surface quality titanium alloy thin plates according to claim 1, characterized in that, The conditions for the low-temperature vacuum diffusion annealing are: under a vacuum degree ≤ 1×10-3 Pa, heat treatment at 430-470℃ for 3-5 hours.

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